textproduct: Albany

WHAT HAS CHANGED

Categorical to Likely PoPs reintroduced across northern Herkimer and Hamilton Counties through this afternoon for ongoing lake effect snow. Adding a mention of the low-end snow squall threat this afternoon with the arctic front. Guidance for Sunday/Monday system continues to tick slightly closer to the coast with the storm track. Added mention of additional cold weather in the wake of Sunday/Monday storm system. All that said, no changes to the existing headlines.

KEY MESSAGES

1) Heavy lake effect snow expected through this evening across far northern Herkimer and Hamilton Counties, with a low chance for isolated snow squalls north and west of the Capital District this afternoon.

2) High confidence for dangerous cold Friday night through Saturday resulting in an increased risk for hypothermia and frostbite.

3) A significant, long duration snowstorm is still expected Sunday into Monday, with widespread travel impacts.

4) Below normal temps continue Tue through the mid and latter portion of the week with Cold Weather Advisory criteria potentially met over the southern Adirondacks and southern Greens Thu morning.

DISCUSSION

KEY MESSAGE 1: As of 2:25 AM EST...Current sfc analysis shows a 1003 mb low located east of James Bay, with a broad 1048 mb sfc high building into the northern Plains. This has set up low-level westerly flow across our region, which is helping direct a band of lake effect snow off of Lake Ontario into far northern Herkimer and Hamilton Counties. 850 mb temps per the latest SPC mesoanalysis are around -18C, and expected to continue falling through the day today. With 850 mb winds of 35-40 kt and inversion heights around 700 mb on both the ALY and BUF 00z soundings, it is not surprising to see the band extending all the way into the Champlain Valley early this morning. Areas north of Old Forge and Raquette Lake have likely already received several inches of snow from this band, with another 4-8 inches on the way as the band should remain in place through at least mid-afternoon, and possibly until early evening. The band may even intensify this morning as inversion heights increase, low-level lapse rates steepen, and there is some added forcing for ascent from CVA as an upper low tracks north of the region. Accordingly, lake effect snow warnings will continue through today for these areas.

The band is expected to be disrupted as an arctic cold front tracks through the region this afternoon. The band will initially drop south through Herkimer and Hamilton Counties, eventually briefly settling south of the Thruway this evening or early tonight. The band will then retract closer to the lake shores as inversion heights quickly lower behind the front, winds veer more to the NW, and the column dries out.

Will also mention that there is a low chance for a couple snow squalls this afternoon with the passage of the arctic front. Favorable ingredients include steepening low-level lapse rates and instability, along with modest convergence along the frontal boundary. However, lack of moisture will be a big limiting factor, and is why main area of concern is limited to areas north and west of the Capital District where some low-level moisture will be enhanced off of Lake Ontario. Ground/air temperatures will be below freezing, so roads could become quickly snow covered in any squalls, along with reduced visibilities.

KEY MESSAGE 2: The arctic front tracks through our region this afternoon as an upper low/TPV tracks north of the region. Confidence remains high for bitterly cold temperatures and wind chills tonight. 850 temps drop to around -30C in the ADKs to -25C in the Mid Hudson Valley tonight, which will translate to sfc temps bottoming out around 0 for the Mid Hudson Valley and as low as the -20s in the ADKs. As if this isn't bad enough, a tightening pressure gradient ahead of the sfc high to our west along with deep mixing in the cold advection regime will support wind gusts possibly up to 30-40 mph, strongest in the typical NW flow channeling areas from the Mohawk Valley through the Capital District and into the Berkshires. This will lead to wind chills ranging from as low as -10 to -15F in the Hudson Valley to <-35F in the Adirondacks. While no changes were made to the existing cold/extreme cold headlines, portions of the Helderbergs and eastern Catskills have some areas that are very close to warning criteria (-25F for those zones) and could be upgraded with the next forecast package if confidence increases.

We remain quite cold Saturday, but the winds diminish as the sfc high builds overhead by Saturday afternoon. Highs will remain below zero for many high terrain areas, and will probably stay in the single digits everywhere else except the immediate I-84 corridor. The high then slides off to our north and east Saturday night and high clouds move in ahead of the next storm system. It will be quite cold again with lows below zero again for most areas except for the valleys south of I-90. However, with weaker winds, wind chills will be very similar to the actual temperature. While a few targeted cold weather advisories could be needed, at this time it looks like most areas will fall short of advisory criteria Saturday night.

KEY MESSAGE 3: Saturday night, a northern stream shortwave dropping into the Great Plains will begin to phase with a moisture-ladden southern stream system tracking across AZ, NM, and TX. As this phase happens, a primary low will develop and track northeastwards towards the Ohio Valley with our sfc high continuing to retreat northeastwards. While there will be a lot of dry air in place that has to be eroded before snow reaches the ground, this should still result in snow overspreading the region by Sunday late morning/early afternoon. Snow intensifies as a secondary/coastal low develops near Atlantic City NJ Sunday afternoon and tracks near or inside of the 40/70 benchmark Sunday night. Snow lingers on Monday as an inverted trough develops from the coastal low back towards the upper trough axis, which will be swinging through the Great Lakes. Snow will be lighter by this time, but could continue through Monday afternoon/evening, especially near and north of I-90, as the upper deformation zone moves overhead.

This system will initially have moisture from the Pacific, with an influx of moisture from both the Gulf and then from the Atlantic as the coastal low intensifies. There will be strong forcing for ascent from isentropic lift as this moist air is lifted over the cold airmass that will be in place, as well as from CVA and the right entrance of the upper jet, especially Sunday afternoon and evening. This lift and moisture will intersect the DGZ, which will be quite deep and low in the atmosphere due to the anomalously cold airmass in place ahead of this system. So, snow to liquid ratios will be above climatology, potentially as high as 15-20:1. The best ratios will be across our northern zones where the DGZ is deeper/lower, but the heaviest qpf will be for our southern areas. Still low confidence on where exactly any mesoscale bands will set up, but based on collaborative CSTAR research with SUNY Albany it looks like we may initially see a laterally translating mesoscale band with the initial warm advection. There are also some signs of a quasi-stationary band developing north and west of the low center Sunday evening or night. Wherever these bands set up, snowfall rates of at least 1-2" per hour will be possible. When all is said and done, a widespread 10-18" of snow will be possible region-wide, with the heaviest amounts where the best/most persistent banding occurs. At this time, the heaviest amounts are expected across the Catskills, Mid Hudson Valley, and southwestern New England, with the lower amounts across our far northern zones.

There are still some subtle points of uncertainty in the forecast. Latest 00z CMC/GFS/NAM have continued with a slight north trend with the sfc low tucked in closer to the coast, likely due to a slightly more amplified downstream ridge. Should this trend north continue, then a mid-level dry slot that is currently expected to remain south of our region late Sunday night into Monday could get into our southern zones, potentially cutting down on snowfall totals there slightly. Since CAMs will generally better handle the convection that is expected to occur over the southeastern CONUS Sat/Sun and resulting downstream ridge amplification from latent heat release, we should get a better idea how much further the trend north/west may continue (if at all) as more hi-res guidance becomes available. Additionally, with E/SE flow, some downslope shadowing is possible in eastern NY, to the west of the southern Greens/Berkshires/Taconics. Nevertheless, confidence is fairly high, especially for this lead time, in warning-level snowfall amounts across most if not all of eastern NY and western New England. This will likely lead to rapidly deteriorating travel conditions through the day Sunday, with the very difficult travel conditions continuing into Monday. The storm should finally pull away to the east of our region Monday afternoon or evening, with snow ending by early Monday night. While it will remain quite cold through this event, winds don't look overly strong, so not expecting any additional cold weather advisories for Sunday-Monday.

KEY MESSAGE 4: In the wake of the significant storm early in the week, a mean mid and upper level trough will persist over the Northeast with below normal temps by 15 to 20 degrees. A clipper low and a cold front will move through Wed-Wed night with a reinforcing shot of arctic air. Highs in the teens and lower 20s (some single numbers over the higher terrain) will give way to lows 0 to 10 below over most of eastern NY and western New England. Lows 5 to 10 below zero over the Adirondack Park/southern Greens with a breeze 5-10 mph may yield some dangerous wind chills or "feels-like" temps around 20- 25 degrees below zero. Cold Weather Advisory conditions may be meet for the southern Dacks and the foothills as well as portions of southern VT. Temps on Thu only recover to the single digits and teens with the arctic air mass firmly in place over the forecast area.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Through 12z Saturday...VFR conditions expected to prevail mostly through the next 24-hrs ending 12Z/Sat for KGFL/KALB/KPSF/KPOU. Some stratocumulus this morning with bases 4-6 kft AGL for KALB/KPSF/KGFL due to the lake effect moisture and an approaching upper level disturbance. An arctic cold front will move through during the afternoon and early evening with isolated-scattered snow showers and flurries. PROB30 groups were used 18Z/Fri to 02Z/SAT for brief MVFR conditions in terms of cigs/vsbys for KALB/KPSF northward. The winds will be southwest to west 6-12 KT this morning with some gusts close to 20 KT, then they will increase from the west to northwest in the afternoon into the early at 15-20 KT with some gusts 25-34 KT with the highest gusts at KALB/KPSF. The winds will gradually subside after midnight and will be northwesterly at 8-15 KT.

Outlook...

Saturday Night: No Operational Impact. NO SIG WX. Sunday: High Operational Impact. Definite SN. Sunday Night: High Operational Impact. Definite SN. Monday: High Operational Impact. Definite SN. Monday Night: Low Operational Impact. Breezy. Chance of SHSN. Tuesday: No Operational Impact. NO SIG WX.

CLIMATE

January 24

Record Cold High Temperatures:

Albany, NY: -1 degrees set in 1882 Glens Falls, NY: 0 degrees set in 1907 Poughkeepsie, NY: 8 degrees set in 1948

Record Cold Low Temperatures:

Albany, NY: -17 degrees set in 1948 Glens Falls, NY: -30 degrees set in 2011 Poughkeepsie, NY: -15 degrees set in 1961

ALY WATCHES/WARNINGS/ADVISORIES

CT...Cold Weather Advisory from 7 PM this evening to 10 AM EST Saturday for CTZ001-013. Winter Storm Watch from Sunday morning through Monday evening for CTZ001-013. NY...Cold Weather Advisory from 7 PM this evening to 10 AM EST Saturday for NYZ040-041-043-047>053-058>061-063>066-083- 084. Winter Storm Watch from Sunday morning through Monday evening for NYZ032-033-038>043-047>054-058>061-063>066-082>084. Extreme Cold Warning from 7 PM this evening to 1 PM EST Saturday for NYZ032-033-038-039-042-054-082. Lake Effect Snow Warning until 7 PM EST this evening for NYZ032-033. MA...Winter Storm Watch from Sunday morning through Monday evening for MAZ001-025. Extreme Cold Warning from 7 PM this evening to 1 PM EST Saturday for MAZ001-025. VT...Winter Storm Watch from Sunday morning through Monday evening for VTZ013>015. Extreme Cold Warning from 7 PM this evening to 1 PM EST Saturday for VTZ013>015.